Electronic throttle valve and natural gas engine air intake control system

Abstract

This invention relates to the field of natural gas engine technology, specifically to an electronic throttle valve and a natural gas engine intake control system. The system includes a valve body and a valve core. The valve body has a cylindrical inner cavity, with an intake port and an outlet port communicating with the inner cavity. Both the intake and outlet ports have square cross-sections. The valve core is rotatably mounted within the inner cavity of the valve body. The valve core has an intake end face and an outlet end face at its front and rear ends, respectively. These end faces are arc-shaped and conform to the cylindrical surface of the valve body's inner cavity. A through hole is formed in the valve core, penetrating the entire valve core. The intake end face of the valve core blocks the intake port, and the outlet end face blocks the outlet port. The airflow first enters the valve body cavity through the intake end and then flows out through the outlet end. The expansion throttling at the intake end and the contraction throttling at the outlet end are spatially separated, improving the stability of the intake airflow.

Description

Technical Field

[0001] This invention relates to the field of natural gas engine technology, specifically to an electronic throttle valve and a natural gas engine intake control system. Background Technology

[0002] In the field of natural gas engines, throttle valves are commonly used to control the precise metering of natural gas and air, thereby controlling the appropriate air-fuel ratio. Traditional throttle valves are generally butterfly valves, with a circular valve plate that rotates around its own diameter, perpendicular to the pipeline axis. The flow characteristics of butterfly valves are typically equal percentage or quick-opening, and the valve opening degree has a non-linear relationship with the effective flow area. When the valve plate rotates from the closed to the open position, there is a significant difference in the flow patterns on both sides of the valve plate. When the butterfly valve is at a medium opening, the nozzle side and the throttle orifice side are formed on the two sides of the valve plate, respectively. The flow patterns on both sides are completely different, and the flow fields interfere with each other. The fluid generates vortices at the edge of the valve plate, causing valve plate vibration. The airflow stability through the butterfly valve is poor, making it difficult to maintain a stable intake flow rate. This is detrimental to the precise metering and control of natural gas or air, and makes it difficult to maintain a stable mixing ratio during premixing, adversely affecting the engine's combustion economy and power stability.

[0003] Moreover, in the existing natural gas supply system, the pressure regulating valve supplies gas to the common rail at a fixed pressure value. When the intake manifold pressure fluctuates with load changes, the gas injection pressure differential changes passively. Even if the opening time of the injection valve remains unchanged, the actual amount of gas entering the intake manifold will still deviate from the target value, resulting in an unstable mixing ratio in the natural gas and air premixing process, which adversely affects the combustion economy and power stability of the engine. Summary of the Invention

[0004] The purpose of this invention is to provide an electronic throttle valve and a natural gas engine intake control system to address the above problems. This invention can improve the stability of intake airflow and avoid unstable intake flow leading to unstable mixing ratio of natural gas and air; it also ensures that the common rail pressure always follows the intake manifold pressure changes, maintaining a constant pressure difference and avoiding pressure difference fluctuations that cause unstable gas flow into the intake manifold, which in turn leads to unstable mixing ratio of natural gas and air.

[0005] To achieve the above objectives, the present invention discloses an electronic throttle valve, comprising a valve body and a valve core. The valve body has a cylindrical inner cavity, and an air inlet port and an air outlet port communicating with the inner cavity are provided on the valve body. The cross-section of the air inlet port and the air outlet port are both square. The valve core is rotatably installed in the inner cavity of the valve body. The front and rear ends of the valve core are respectively provided with an air inlet end face and an air outlet end face. The air inlet end face and the air outlet end face are arc-shaped end faces adapted to the cylindrical surface of the inner cavity of the valve body. A through hole is opened on the valve core, and the through hole penetrates the valve core. The air inlet end face of the valve core is used to block the air inlet port, and the air outlet end face of the valve core is used to block the air outlet port.

[0006] The opening area of ​​the inlet and outlet ports is adjusted by controlling the rotation angle of the valve core, thereby regulating the intake flow rate. The airflow first enters the valve body chamber through the inlet end and then flows out through the outlet end. The expansion throttling at the inlet end and the contraction throttling at the outlet end are spatially separated, avoiding the flow field interference and valve plate vibration problems caused by the different flow states on the nozzle side and the throttling orifice side in butterfly valves. This improves the stability of the intake flow rate and prevents unstable natural gas and air mixing ratios due to unstable intake flow. The ventilation area of ​​the square port is controlled by the arc-shaped end face. The effective flow area of ​​the square port is limited by a fixed height and a variable length. The dimension in the height direction is constant, while the dimension in the length direction changes with the rotation angle of the valve core. The exposed area of ​​the port increases smoothly with the increase of the valve core rotation angle, resulting in a flow linearity superior to that of a butterfly valve.

[0007] Preferably, the cross-section of the through holes is square, and the through holes penetrate the valve core along the left-right direction. The square cross-section is simple to process, does not require complex curved surface forming processes, and has low manufacturing costs.

[0008] Preferably, the inlet and outlet ports have the same cross-sectional dimensions, and the inlet and outlet end faces are symmetrically arranged. When the valve core rotates, the opening area of ​​the inlet port is always equal to the opening area of ​​the outlet port. The identical cross-sectional dimensions of the inlet and outlet ports, and the fact that their opening areas remain equal when the valve core rotates, ensure that the flow areas at the inlet and outlet ends change synchronously.

[0009] Preferably, the side length of the square cross-section of the air inlet port and the air outlet port is smaller than the diameter of the valve body cavity. This ensures that the ports are completely within the circular cross-section of the valve body cavity, allowing the valve core to completely cover and seal the ports when in the closed position.

[0010] Preferably, symmetrical arc-shaped grooves are formed on both the left and right ends of the valve core, and a through hole passes through both arc-shaped grooves. The presence of arc-shaped grooves on both ends of the valve core, symmetrically arranged, and the through hole passing through both arc-shaped grooves ensures a smooth flow path for airflow, reducing flow resistance within the valve core.

[0011] Preferably, weight-reducing chambers are provided at both the front and rear ends of the valve core. The weight-reducing chambers can reduce the weight of the valve core and reduce the energy consumption required for valve core rotation.

[0012] Preferably, the valve body includes a valve body main body, an upper end cover, and a lower end cover. The air inlet port and the air outlet port are located on the valve body main body, and the upper end cover and the lower end cover are used to install on the upper and lower ends of the valve body main body. The split structure facilitates the assembly and disassembly of the valve core, facilitates the maintenance of the valve core, and reduces maintenance costs.

[0013] A natural gas engine intake control system includes an air filter, a turbocharger, an intercooler, an electronic throttle, an intake manifold, an exhaust manifold, a high-pressure filter, a follow-up pressure regulating valve, a common rail gas line, and an injection valve. The air filter, turbocharger, intercooler, electronic throttle, and intake manifold are connected in sequence. The electronic throttle is connected to the inlet of the intake manifold, and the outlet of the intake manifold is connected to the air intake of the engine. The inlet of the exhaust manifold is connected to the exhaust outlet of the engine, and the outlet of the exhaust manifold is connected to the turbocharger. The intake manifold is equipped with an intake pressure sensor to detect its pressure, and the common rail is equipped with a gas pressure sensor to detect its pressure. It also includes an electronic control unit, which is connected to the intake pressure sensor and the gas pressure sensor.

[0014] Gas passes through a high-pressure filter on the pipeline, and after being regulated by a follow-up pressure regulating valve, it enters the common rail. This follow-up pressure regulating valve supplies gas according to a set pressure value, and the electronic control unit can adjust the pressure based on the pressure difference between the intake manifold and the common rail. When the pressure difference increases, the follow-up pressure regulating valve increases the input pressure of the common rail downstream of the valve; when the pressure difference decreases, the follow-up pressure regulating valve decreases the input pressure of the common rail, ensuring that the pressure of the common rail always follows the pressure changes of the intake manifold, maintaining a constant pressure difference. This creates the prerequisite for precise control of the air-fuel ratio and avoids instability in the amount of gas entering the intake manifold due to pressure difference fluctuations, which in turn leads to an unstable mixing ratio of natural gas and air.

[0015] Preferably, the electronic control unit includes an analog signal processing module, a speed pulse processing module, a working condition analysis module, an intake air volume feedforward control module, a control strategy scheduler, a throttle target opening module, and a drive output stage; The analog signal processing module is used to acquire sensor signals and perform signal processing; the speed pulse processing module is used to receive pulse signals and calculate engine speed; the operating condition analysis module is used to determine the current operating condition mode based on engine parameters; the analog signal processing module, speed pulse processing module and operating condition analysis module interact with each other and provide data to the intake air feedforward control module; the intake air feedforward control module is used to calculate the target intake air flow. The output of the intake volume feedforward control module is connected to the input of the control strategy scheduler; the control strategy scheduler is used to select the corresponding control parameters according to the current operating mode. The output of the control strategy scheduler is connected to the input of the throttle target opening module; the throttle target opening module is used to generate a throttle opening control signal based on the target intake air flow. The output of the throttle target opening module is connected to the input of the drive output stage. The drive output stage is used to generate a drive signal based on the throttle opening control signal. The output of the drive output stage is connected to the electronic throttle.

[0016] By setting up an analog signal processing module, a speed pulse processing module, a working condition analysis module, an intake air volume feedforward control module, a control strategy scheduler, a throttle target opening module, and a drive output stage, the working condition analysis module determines the current working condition mode based on parameters such as engine speed and accelerator pedal position. The intake air volume feedforward control module calculates the target intake air flow based on the working condition mode, and the throttle target opening module calculates the target throttle opening, thereby controlling the throttle drive mechanism and controlling the throttle intake air flow. Moreover, by using the above-mentioned electronic throttle with stable output flow, the stability of the intake air volume of the intake system can be improved.

[0017] Preferably, the analog signal processing module, the speed pulse processing module, and the operating condition analysis module interact with each other via a data bus and / or shared memory, and provide data to the intake air feedforward control module via the data bus and / or shared memory.

[0018] In summary, the beneficial effects of the present invention are as follows: The opening area of ​​the inlet and outlet ports is adjusted by controlling the rotation angle of the valve core, thereby regulating the intake flow rate. The airflow first enters the valve body chamber through the inlet end and then flows out through the outlet end. The expansion throttling at the inlet end and the contraction throttling at the outlet end are spatially separated, avoiding the flow field interference and valve plate vibration problems caused by the different flow states on the nozzle side and the throttling orifice side in butterfly valves. This improves the stability of the intake flow rate and prevents unstable natural gas and air mixing ratios due to unstable intake flow. The ventilation area of ​​the square port is controlled by the arc-shaped end face. The effective flow area of ​​the square port is limited by a fixed height and a variable length. The dimension in the height direction is constant, while the dimension in the length direction changes with the rotation angle of the valve core. The exposed area of ​​the port increases smoothly with the increase of the valve core rotation angle, resulting in a flow linearity superior to that of a butterfly valve. Attached Figure Description

[0019] Figure 1 A three-dimensional structural diagram of an electronic throttle valve; Figure 2 A cross-sectional view of the electronic throttle body in its fully open position; Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure along the AA direction; Figure 4 A cross-sectional view of the electronic throttle body in the fully closed state; Figure 5 for Figure 4 A schematic diagram of the cross-sectional structure along the BB direction; Figure 6 A cross-sectional view of the electronic throttle valve in a partially open state; Figure 7 for Figure 5 A schematic diagram of the cross-sectional structure in the CC direction; Figure 8 This is a schematic diagram of the control principle of Example 2; Figure 9 This is a schematic diagram of the control principle in Example 3; Figure 10 This is a schematic diagram of the intake volume feedforward calculation logic; Figure 11 This is a top view of the throttle window.

[0020] In the diagram: valve body 1, inner cavity 10, air inlet port 11, air outlet port 12, valve body main body 13, upper end cover 14, lower end cover 15, valve core 2, air inlet end face 20, air outlet end face 21, through hole 22, arc groove 23, weight reduction chamber 24, rotating shaft 3, injection valve 4, air inlet pressure sensor 5, gas pressure sensor 6. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0022] The following is a description of preferred embodiments of the present invention in conjunction with the accompanying drawings. Example 1:

[0023] like Figures 1 to 7 As shown, an electronic throttle valve includes a valve body 1 and a valve core 2. The valve body 1 has a cylindrical inner cavity 10. The valve body 1 is provided with an air inlet port 11 and an air outlet port 12 communicating with the inner cavity 10. The cross-section of the air inlet port 11 and the air outlet port 12 is square. The valve core 2 is rotatably installed in the inner cavity 10 of the valve body 1. The front and rear ends of the valve core 2 are respectively provided with an air inlet end face 20 and an air outlet end face 21. The air inlet end face 20 and the air outlet end face 21 are arc-shaped end faces adapted to the cylindrical surface of the inner cavity 10 of the valve body 1. A through hole 22 is opened on the valve core 2, and the through hole 22 penetrates the valve core 2. The air inlet end face 20 of the valve core 2 is used to block the air inlet port 11, and the air outlet end face 21 of the valve core 2 is used to block the air outlet port 12.

[0024] The opening area of ​​the inlet port 11 and outlet port 12 is adjusted by controlling the rotation angle of the valve core 2, thereby regulating the intake flow rate. The curvature of the arc-shaped end face is the same as the curvature of the cylindrical surface of the inner cavity 10 of the valve body 1. During the rotation of the valve core 2, the arc-shaped end face always fits against the cylindrical surface of the inner cavity 10. The airflow first enters the chamber of the valve body 1 through the inlet end and then flows out through the outlet end. The expansion throttling at the inlet end and the contraction throttling at the outlet end are spatially separated, avoiding the mutual interference of flow fields and valve plate vibration caused by the different flow states on the nozzle side and the throttling orifice side in the butterfly valve, thus improving the stability of the intake flow rate. The ventilation area of ​​the square port is controlled by the arc-shaped end face. The effective flow area of ​​the square port is limited by both the fixed height and the variable length. The dimension in the height direction is constant, while the dimension in the length direction changes with the rotation angle of the valve core 2. The exposed area of ​​the port increases smoothly with the increase of the rotation angle of the valve core 2, and the linearity of the flow rate is better than that of the butterfly valve.

[0025] As a preferred embodiment, the cross-section of the through hole 22 is square, and the through hole 22 penetrates the valve core 2 along the left-right direction. The square cross-section is simple to process, does not require complex curved surface forming process, and has low manufacturing cost. The through hole 22 penetrates the valve core 2 along the left-right direction, and when fully open, the through hole 22 is completely aligned and connected with the air inlet port 11 and the air outlet port 12, and the airflow path is smooth.

[0026] The inlet port 11 and outlet port 12 have the same cross-sectional dimensions, and the inlet end face 20 and outlet end face 21 are symmetrically arranged. When the valve core 2 rotates, the opening area of ​​the inlet port 11 and the opening area of ​​the outlet port 12 are always equal. The identical cross-sectional dimensions of the inlet port 11 and outlet port 12, and the consistent opening area of ​​the inlet port 11 and outlet port 12 when the valve core 2 rotates, ensure that the flow area at the inlet and outlet ends changes synchronously.

[0027] In a preferred embodiment, the side length of the square cross-section of the air inlet port 11 and the air outlet port 12 is smaller than the diameter of the inner cavity 10 of the valve body 1. Because the side length of the square cross-section of the air inlet port 11 and the air outlet port 12 is smaller than the diameter of the inner cavity 10 of the valve body 1, the ports are completely located within the circular cross-section of the inner cavity 10 of the valve body 1, and the valve core 2 can completely cover and seal the ports when in the closed position.

[0028] The valve core 2 has convex arc-shaped end faces at both its front and rear ends, namely the inlet end face 20 and the outlet end face 21. The convex arc-shaped end faces, serving as the inlet end face 20 and the outlet end face 21, are adapted to the cylindrical surface of the inner cavity 10 of the valve body 1, ensuring the coaxiality of the valve core 2's rotation within the inner cavity 10 of the valve body 1, which is beneficial for improving the accuracy of flow control.

[0029] In a preferred embodiment, the valve core 2 has arc-shaped grooves 23 on both its left and right ends, symmetrically arranged, with a through hole 22 penetrating both grooves 23. The arc-shaped grooves 23 on both ends of the valve core 2 and the through hole 22 penetrating both grooves ensure smooth airflow through the through hole 22, reducing flow resistance within the valve core 2. In another preferred embodiment, the valve core 2 has weight-reducing chambers 24 on both its front and rear ends. The weight-reducing chambers 24 reduce the weight of the valve core 2, thus reducing the energy consumption required for its rotation.

[0030] In a preferred embodiment, the weight-reducing cavity 24 extends through the valve core 2 along its height. The weight-reducing cavity 24 extending through the valve core 2 further reduces its weight and facilitates its processing and shaping.

[0031] In a preferred embodiment, the valve body 1 includes a valve body 13, an upper end cover 14, and a lower end cover 15. An inlet port 11 and an outlet port 12 are located on the valve body 13. The upper end cover 14 and the lower end cover 15 are mounted on the upper and lower ends of the valve body 13. Specifically, the upper end cover 14 and the lower end cover 15 are bolted to the valve body 13. This split structure facilitates the assembly and disassembly of the valve core 2, simplifying maintenance and reducing maintenance costs.

[0032] The electronic throttle valve also includes a rotating shaft 3, which passes through the center of the valve core 2 and is fixed to the valve core 2. The two ends of the rotating shaft 3 are rotatably mounted on the upper end cover 14 and the lower end cover 15, respectively. The rotating shaft 3 allows the valve core 2 to be rotatably mounted on the valve body 1. Specifically, the valve core 2 has a mounting hole for the rotating shaft 3 to pass through, a rotating shaft pin hole is formed on the rotating shaft 3, and a valve core pin hole corresponding to the rotating shaft pin hole is formed on the valve core 2. A cylindrical pin is interference-fitted into the rotating shaft pin hole and the valve core pin hole, thereby fixing the rotating shaft 3 to the valve core 2. The upper end of the rotating shaft 3 passes through the upper end cover 14 and connects to a drive mechanism. The drive mechanism drives the rotating shaft 3 to rotate, thereby rotating the valve core 2 and adjusting the intake airflow. The drive mechanism can be a motor, and the output shaft of the motor is connected to the upper end of the rotating shaft 3 via a coupling. The electronic control unit can be electrically connected to the drive mechanism, thereby controlling the drive mechanism to adjust the angle of the valve core 2. In actual use, a driven gear can be fixed to the upper end of the rotating shaft 3, and a driving gear can be installed on the motor output shaft. The rotating shaft 3 can be driven to rotate through the meshing connection between the driving gear and the driven gear. The drive mechanism is a conventional mechanism and will not be described in detail here.

[0033] The arc-shaped end face covers a central angle of 90° in the circumferential direction, allowing the valve core 2 to rotate 90° from fully closed to fully open, thus achieving opening adjustment throughout the entire stroke range. The rotation angle of the valve core 2 is θ. When θ=0°, the valve core 2 is in the closed position, and the electronic throttle is in the fully closed state; when θ=90°, the valve core 2 is in the fully open position, and the electronic throttle is in the fully open state.

[0034] In the closed position (θ=0°), the intake end face 20 of valve core 2 completely blocks the intake port 11, and the outlet end face 21 of valve core 2 completely blocks the outlet port 12, blocking airflow through the electronic throttle. At this time, the electronic throttle opening is 0, and the intake flow is zero.

[0035] As the valve core 2 rotates from the closed position to the open position, the intake end face 20 gradually moves away from the intake port 11, and the outlet end face 21 gradually moves away from the outlet port 12, with the opening areas of the intake port 11 and the outlet port 12 increasing synchronously. When the valve core 2 rotates to the fully open position (θ=90°), the intake port 11 and the outlet port 12 are fully exposed, and the through hole 22 is directly connected to the intake port 11 and the outlet port 12. The electronic throttle opening reaches its maximum, and the airflow passes through the intake port 11, the through hole 22, and the outlet port 12 through the electronic throttle. Example 2:

[0036] like Figure 8 As shown, a natural gas engine intake control system includes an air filter, a turbocharger, an intercooler, an electronic throttle, an intake manifold, an exhaust manifold, a high-pressure filter, a follow-up pressure regulating valve, a common rail gas pipe, and an injection valve 4. The air filter, turbocharger, intercooler, electronic throttle, and intake manifold are connected in sequence. The electronic throttle is connected to the inlet of the intake manifold, and the outlet of the intake manifold is connected to the air intake of the engine. The inlet of the exhaust manifold is connected to the exhaust outlet of the engine, and the outlet of the exhaust manifold is connected to the turbocharger. An intake pressure sensor 5 is installed on the intake manifold to detect its pressure, and a gas pressure sensor 6 is installed on the common rail to detect its pressure. It also includes an electronic control unit (ECU), which is connected to the intake pressure sensor 5 and the gas pressure sensor 6. The ECU is also electrically connected to the follow-up pressure regulating valve and the electronic throttle. The ECU adjusts the follow-up pressure regulating valve based on the pressure difference between the intake manifold and the common rail, ensuring that the pressure in the common rail follows the pressure changes in the intake manifold and maintains a constant pressure difference. The follow-up pressure regulating valve is an electronically controlled follow-up valve, which can specifically be a fuel proportioning valve. The ECU can also control the opening of the electronic throttle, thereby regulating the air intake flow.

[0037] Gas passes through a high-pressure filter on the pipeline, and after being regulated by a follow-up pressure regulating valve, it enters the common rail. This follow-up pressure regulating valve supplies gas according to a set pressure value and can provide feedback to the electronic control unit based on the pressure difference between the intake manifold and the common rail for adjustment. When the pressure difference increases, the follow-up pressure regulating valve increases the input pressure of the common rail downstream of the valve; when the pressure difference decreases, the follow-up pressure regulating valve decreases the input pressure of the common rail, so that the pressure of the common rail always follows the pressure change of the intake manifold and maintains a constant pressure difference.

[0038] The injection valve 4 installed on the common rail allows pressurized fuel gas to enter the intake manifold, where it premixes with air and burns to produce power. The opening and closing time of the injection valve 4 is controlled by the engine speed signal, which is input to the electronic control unit (ECU). The ECU adjusts the opening and closing time of the injection valve 4 to achieve precise control of the fuel gas flow. Air passes through a filter in the pipeline, is compressed by the turbine to form high-pressure air, and is cooled by the intercooler before entering the electronic throttle. The electronic throttle controls the airflow area by rotating the valve core 2. The minimum rotation of the valve core 2 is 0°, which is the maximum opening of the electronic throttle, and the minimum is 90°, at which point the electronic throttle is closed. By adjusting the angle of the throttle valve core, the airflow through the throttle is adjusted, thereby regulating the air-fuel ratio entering the intake manifold and controlling the air-fuel ratio of the mixture. Example 3:

[0039] like Figures 9 to 11 As shown, a natural gas engine intake control system includes an electronic control unit (ECU). The ECU includes an analog signal processing module, a speed pulse processing module, an operating condition analysis module, an intake volume feedforward control module, a control strategy scheduler, a throttle target opening module, and a drive output stage.

[0040] The analog signal processing module, the speed pulse processing module, and the operating condition analysis module interact with each other and provide data to the intake air volume feedforward control module. More specifically, the analog signal processing module, the speed pulse processing module, and the operating condition analysis module interact with each other via a data bus and / or shared memory, and provide data to the intake air volume feedforward control module via the data bus and / or shared memory.

[0041] The analog signal processing module is used to acquire and process sensor signals. It receives sensor signals through multiple analog signal acquisition channels. The signals acquired by the module are continuously changing analog signals, including boost pressure, boost temperature, intake air temperature, intake air pressure, throttle opening feedback, and accelerator pedal position. The module processes the received analog signals sequentially as follows: filtering to remove high-frequency noise; analog-to-digital conversion to convert analog voltage signals to digital quantities; digital filtering to further smooth the digital signal; and dimensional conversion to convert digital quantities to their corresponding physical dimensions, such as converting voltage values ​​to temperature or pressure values. The processed data is then provided to the operating condition analysis module and the intake air feedforward control module via a data bus and / or shared memory.

[0042] The engine speed pulse processing module receives pulse signals and calculates engine speed. The signals acquired by this module are pulse signals, including crankshaft position signals and camshaft position signals, used to calculate engine speed and determine crankshaft angle and engine operating phase. This module shapes the received pulse signals, converting irregular pulse waveforms into standard square waves. It identifies the rising and falling edges of each pulse through edge detection and measures the time interval between adjacent pulses (period measurement), calculating the real-time engine speed based on the pulse period. The module also verifies the validity of the calculation results, determining if the speed is within a reasonable range. The processed speed data is then provided to the operating condition analysis module via the data bus and / or shared memory.

[0043] The operating condition analysis module determines the current operating mode based on engine parameters. It acquires data from the analog signal processing module and the speed pulse processing module via the data bus and / or shared memory, including parameters such as engine speed, intake pressure, intake temperature, boost pressure, boost temperature, and accelerator pedal position. The module determines the current engine operating condition based on these parameters and their rate of change. When the engine speed is stable near the target idle speed and the accelerator pedal position is zero, it is determined to be in idle condition; when the engine speed and load remain essentially unchanged within a set time and the accelerator pedal position is greater than zero, it is determined to be in steady-state condition; when the rate of decrease in engine speed exceeds a preset threshold, it is determined to be in speed-drop condition. The operating condition analysis module outputs the determination result as an operating mode signal, which is provided to the intake air feedforward control module via the data bus and / or shared memory.

[0044] The intake air volume feedforward control module is used to calculate the target intake air flow rate. This module determines the basic intake air volume based on engine speed and load, and performs feedforward compensation according to changes in operating conditions. During operating condition switching, the intake air volume feedforward control module adjusts the target intake air flow rate according to the changes in operating conditions, making the target intake air flow rate more suitable for the current operating conditions. The calculated target intake air flow rate is then output to the control strategy scheduler.

[0045] The output of the intake air volume feedforward control module is connected to the input of the control strategy scheduler, transmitting the target intake air flow rate to the scheduler. The control strategy scheduler has two main core strategies: First, it calculates the target fuel mass flow rate based on the target intake air flow rate and the target air-fuel ratio. The target fuel mass flow rate is based on the linearization coefficient of the fuel injector or fuel proportional valve, which yields the injector pulse width or the opening of the fuel proportional valve, thus enabling appropriate air-fuel ratio matching. Second, it calculates the target throttle opening that matches the target intake air flow rate based on the hydrodynamic formulas for airflow through the throttle body. The intake air mass flow rate through the electric throttle can be estimated using the following formula:

[0046]

[0047]

[0048]

[0049]

[0050] In the formula, The mass flow rate of the medium passing through the throttle valve is the rotation angle. It is a function of the pressure before the throttle, the pressure after the throttle, and the temperature of the air medium. The effective flow area of ​​the throttle valve. This refers to the rotation angle of the throttle valve. The pressure before the throttle body, The pressure after the throttle body. R is the temperature of the air flowing through the throttle valve, and R is the gas constant. The adiabatic coefficient, Let H be the radius of the rotating body inside the throttle valve, and let H be the height of the rotating body inside the throttle valve. The rotating body inside the throttle body rotates. The length of the arc traveled by the angle. The calculation can be divided into two cases: sonic and subsonic. The formula can be directly applied during the calculation.

[0051] The brilliance of this throttle body and fluid flow calculation method lies in the flow area of ​​the throttle body. Angle of rotation of the internal rotating body of the throttle body The angles are perfectly linear. The target intake airflow is obtained through the intake volume feedforward control module and is a known quantity. Pressure, temperature, etc., are measured by sensors, and the throttle opening corresponding to the target intake air mass flow rate can be directly obtained through the inverse operation of the formula. This design can greatly improve the accuracy and precision of air mass flow through the throttle valve, avoiding the complex calculations caused by the nonlinearity of the butterfly valve throttle valve.

[0052] The electronic control unit reads operating parameters such as speed, load, and throttle commands from the data bus or shared memory, and queries the basic intake air volume accordingly. Then it determines whether a torque-based strategy is currently being used. If so, it queries the preset torque MAP and calculates the target air volume through the torque-to-volume strategy. If not, it obtains the target speed setting and speed feedback value, and the PID controller calculates the required intake air volume based on the speed deviation. The results of the two paths are finally combined to output the target air mass flow rate.

[0053] The output of the control strategy scheduler is connected to the input of the throttle target opening module.

[0054] The throttle target opening module generates a throttle opening control signal based on the target intake airflow. This module connects to the control strategy scheduler, receiving the throttle target opening parameters output by the scheduler and simultaneously obtaining the target intake airflow from the intake volume feedforward control module. The module calculates the target throttle opening based on the target intake airflow, employing a control strategy combining inverse function calculation, feedforward voltage calculation, and interference compensation, and corrects it through closed-loop feedback of the actual intake airflow. The calculated target throttle opening is then converted into a PWM duty cycle control signal and output to the drive output stage.

[0055] The output of the throttle target opening module is connected to the input of the drive output stage, which generates a drive signal based on the throttle opening control signal. The drive output stage includes a PWM drive output stage. The PWM drive output stage outputs a PWM drive signal to control the throttle opening. The output of the drive output stage is connected to the electronic throttle valve in Embodiment 1. By controlling the drive mechanism of the electronic throttle valve, the rotation of the shaft and valve core is controlled, thereby stabilizing the intake airflow.

[0056] This invention establishes an analog signal processing module, a speed pulse processing module, a working condition analysis module, an intake air volume feedforward control module, a control strategy scheduler, a throttle target opening module, and a drive output stage. The working condition analysis module determines the current working condition mode based on parameters such as engine speed and accelerator pedal position. The intake air volume feedforward control module calculates the target intake air flow rate based on the working condition mode, and the throttle target opening module calculates the target throttle opening, thereby controlling the throttle drive mechanism and controlling the throttle intake air flow rate. The electronic throttle in Embodiment 1 avoids flow field interference and valve plate vibration problems through structural improvements, stabilizing the actual intake air volume at a given opening. The control system in this embodiment calculates the target intake air flow rate based on the current working condition mode and performs feedforward compensation based on changes in working conditions. Through working condition identification, the target intake air flow rate is made more closely matched to the current working conditions. The combined effect of these two mechanisms makes the actual intake air volume closer to the target value, thereby further improving the stability of the intake airflow in the intake system.

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An electronic throttle valve, characterized in that... The valve body (1) includes a valve body (1) and a valve core (2). The valve body (1) has a cylindrical inner cavity (10). The valve body (1) is provided with an air inlet port (11) and an air outlet port (12) that communicate with the inner cavity (10). The cross-section of the air inlet port (11) and the air outlet port (12) is square. The valve core (2) is rotatably installed in the inner cavity (10) of the valve body (1). The front and rear ends of the valve core (2) are respectively provided with an air inlet end face (20) and an air outlet end face (21). The air inlet end face (20) and the air outlet end face (21) are arc-shaped end faces that are adapted to the cylindrical surface of the inner cavity (10) of the valve body. The valve core (2) is provided with a through hole (22) that penetrates the valve core (2). The air inlet end face (20) of the valve core (2) is used to block the air inlet port (11), and the air outlet end face (21) of the valve core (2) is used to block the air outlet port (12).

2. The electronic throttle valve as described in claim 1, characterized in that, The cross-section of the through hole (22) is square, and the through hole (22) penetrates the valve core (2) along the left and right direction.

3. An electronic throttle valve as described in claim 1, characterized in that, The inlet port (11) and the outlet port (12) have the same cross-sectional dimensions. The inlet end face (20) and the outlet end face (21) are arranged symmetrically. When the valve core (2) rotates, the opening area of ​​the inlet port (11) and the opening area of ​​the outlet port (12) are always equal.

4. An electronic throttle valve as described in claim 1, characterized in that, The side length of the square cross-section of the air inlet port (11) and the air outlet port (12) is smaller than the diameter of the valve body cavity (10).

5. An electronic throttle valve as described in claim 2, characterized in that, The valve core (2) has arc-shaped grooves (23) on its left and right ends respectively, and the two arc-shaped grooves (23) are symmetrically arranged. The through hole (22) passes through the two arc-shaped grooves (23).

6. An electronic throttle valve as described in claim 5, characterized in that, Weight reduction chambers (24) are respectively provided on the front and rear ends of the valve core (2).

7. An electronic throttle valve as described in claim 5, characterized in that, The valve body (1) includes a valve body body (13), an upper end cover (14) and a lower end cover (15). The air inlet port (11) and the air outlet port (12) are opened on the valve body body (13). The upper end cover (14) and the lower end cover (15) are respectively installed on the upper and lower ends of the valve body body (13).

8. A natural gas engine intake control system, characterized in that, Includes an air filter, a turbocharger, an intercooler, an electronic throttle valve as described in any one of claims 1 to 7, an intake manifold, an exhaust manifold, a high-pressure filter, a follow-up pressure regulating valve, a common rail gas pipe, and an injection valve (4); The air filter, turbocharger, intercooler, electronic throttle, and intake manifold are connected in sequence. The electronic throttle is connected to the inlet of the intake manifold, and the outlet of the intake manifold is connected to the air intake of the engine. The inlet of the exhaust manifold is connected to the exhaust port of the engine, and the outlet of the exhaust manifold is connected to the turbocharger. The intake manifold is equipped with an intake pressure sensor (5) for detecting its pressure, and the common rail is equipped with a gas pressure sensor (6) for detecting its pressure. It also includes an electronic control unit, which is connected to the intake pressure sensor (5) and the gas pressure sensor (6).

9. A natural gas engine intake control system as described in claim 8, characterized in that, The electronic control unit includes an analog signal processing module, a speed pulse processing module, a working condition analysis module, an intake air volume feedforward control module, a control strategy scheduler, a throttle target opening module, and a drive output stage; The analog signal processing module is used to acquire sensor signals and perform signal processing. The speed pulse processing module is used to receive pulse signals and calculate engine speed. The operating condition analysis module is used to determine the current operating condition mode based on engine parameters. The analog signal processing module, the speed pulse processing module, and the operating condition analysis module interact with each other and provide data to the intake air feedforward control module. The intake air feedforward control module is used to calculate the target intake air flow rate. The output of the intake volume feedforward control module is connected to the input of the control strategy scheduler; the control strategy scheduler is used to select the corresponding control parameters according to the current operating mode. The output of the control strategy scheduler is connected to the input of the throttle target opening module; the throttle target opening module is used to generate a throttle opening control signal based on the target intake air flow. The output terminal of the throttle target opening module is connected to the input terminal of the drive output stage. The drive output stage is used to generate a drive signal according to the throttle opening control signal. The output terminal of the drive output stage is connected to the electronic throttle.

10. A natural gas engine intake control system as described in claim 9, characterized in that, The analog quantity processing module, the speed pulse processing module, and the operating condition analysis module interact with each other via a data bus and / or shared memory, and provide data to the intake volume feedforward control module via the data bus and / or shared memory.

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